1. Field of the Invention
The present invention relates to an FF/REW control apparatus capable of performing high-speed FF/REW, a FF/REW control method and a medium in which an FF/REW control program is recorded.
2. Description of the Prior Art
Conventionally, in this type of FF/REW control apparatus, rotational periods of a video tape supply reel and a take-up reel are detected. Upon high-speed FF (Fast Forward) or high-speed REW (Rewind), a hub diameter is discriminated based on both rotational periods, and a tape running speed is controlled in accordance with the hub diameter. Generally, a VHS (Video Home System)-format video tape has either a hub diameter of 26 mm or 62 mm. If high-speed REW control or the like for a video tape having a hub diameter of 26 mm, (hereinafter referred to as a xe2x80x9cthin hubxe2x80x9d) is performed on a video tape having a hub diameter of 62 mm (hereinafter referred to as a xe2x80x9cthick hubxe2x80x9d), then the REW operation cannot be stopped at a tape end position, but rather further REW operation occurs. Accordingly, the tape transport speed is controlled in accordance with the hub diameter.
The hub diameter discrimination utilizes the fact that if the rotational periods of the supply reel Ts and take-up reel Tt are substituted into an expression:
A=Ts**2+Tt**2,
xe2x80x9cAxe2x80x9d has a fixed value in accordance with hub diameter. That is,
If 3 less than A holds, then the hub diameter is 62 mm
If 1.8 less than A less than 3 holds, then the hub diameter is 26 mm
Thus, the hub diameter can be discriminated.
In the conventional apparatus, prior to high-speed FF/REW, a normal FF/REW is performed for several seconds, in order to detect the rotational periods of the supply reel and the take-up reel. Then, the above value A is obtained based on the detected values. The acceleration and deceleration upon high-speed FF/REW are then controlled in accordance with the hub diameter discriminated from the calculation.
On the other hand, Japanese Published Unexamined Patent Application No. Hei 3-95751 discloses performing the normal FF/REW for several seconds to detect the rotational speeds of the supply reel and the take-up reel prior to the high-speed FF/REW, and then calculating a ratio N between the rotational speeds. When the ratio N falls within a predetermined value range, a change rate is calculated based on the change of the ratio N over time. Utilizing the fact that the change rate of the ratio N differs for the case where the hub is out of specification and for the case where the hub is a thick hub, it is discriminated whether the hub is a thick hub or a hub out of specification (hereinafter referred to as an xe2x80x9cout-of-spec hubxe2x80x9d). The high-speed FF/REW is performed in accordance with the result of the discrimination. Further, deceleration is performed when the ratio N is either a predetermined or greater value or when the ratio N is a reciprocal of its initial value. Then, the FF/REW is terminated.
The above-described conventional FF/REW control apparatuses have the following problems.
In the former apparatus (where the hub diameter is discriminated by performing normal FF/REW for several seconds prior to high-speed FF/REW and control is performed in accordance with the hub diameter), when a user requests execution of high-speed FF/REW, the operating mode cannot be quickly shifted to the high-speed FF/REW mode. Further, because a software sequence is required to perform the hub diameter discrimination, a ROM capacity for this purpose is required.
On the other hand, in the latter apparatus, the rotational periods of the supply reel and the take-up reel are detected by performing normal FF/REW for several seconds prior to high-speed FF/REW, and the high-speed FF/REW is controlled in accordance with the ratio between these rotational speeds. In this control, since the rotational period ratio N is discriminated every time before high-speed FF/REW is performed, there is a possibility that in controlling a thin hub video tape, if FF/REW has been stopped once and is then performed again, thick hub control may be performed on the video tape.
Further, in this apparatus, in order to perform control in accordance with the respective hub diameters, the discrimination of the ratio N, the detection of time change of the ratio N, and the discrimination of whether or not the value of the ratio N is a reciprocal of its initial value, are made. Accordingly, in constructing this type of high-speed FF/REW apparatus, the processing load imposed by the software is heavy, and the necessary ROM capacity is large.
The present invention has been made in consideration of the above problems, and has as its objects to provide: a FF/REW control apparatus capable of performing high-speed tape forward (high-speed FF/REW) by a simple control, a FF/REW control method, and a medium in which a FF/REW control program is recorded.
According to the present invention, the foregoing objects are attained by providing a FF/REW (Fast Forward/Rewind) control apparatus comprising: a speed-variable tape forward mechanism, in which a video tape is loaded, for performing FF (Fast Forward) or REW (Rewind) control while variably controlling a tape running speed; a reel rotational-period detection unit for detecting rotational periods of a supply reel and a take-up reel of the video tape loaded in the speed-variable tape forward mechanism; a rotational-period-ratio calculation unit for calculating a rotational period ratio between the rotational periods of the supply reel and the take-up reel detected by the reel rotational-period detection unit; and a tape-forward control unit, capable of performing high-speed tape forward for the case where a hub diameter of the video tape is a thick hub diameter and for the case where the hub diameter is a thin hub diameter by controlling the speed-variable tape forward mechanism. The tape-forward control unit performs, upon FF/REW operation request, high-speed tape forward control for the case where the hub diameter is the thin hub diameter when the rotational period ratio calculated by the rotational-period-ratio calculation unit has a value other than values predetermined for the case where the video tape has the thick hub diameter.
In accordance with the present invention constructed as described above, when a video tape is loaded into the speed-variable tape forward mechanism and tape forward is requested, the reel rotational-period detection unit detects the rotational periods of a supply reel and a take-up reel of the video tape, and the rotational-period-ratio calculation unit calculates the rotational period ratio between the rotational periods of the supply reel and the take-up reel. Further, the tape-forward control unit is capable of performing high-speed tape forward for the case where the hub diameter of the video tape is the thick hub diameter and for the case where the hub diameter of the video tape is the thin hub diameter, by controlling the speed-variable tape forward mechanism. When FF/REW is performed in the FF/REW control apparatus, the rotational-period-ratio calculation unit calculates the rotational period ratio. If the rotational period ratio has a value other than values for a video tape having the thick hub diameter, the tape-forward control unit performs the high-speed tape forward control for the case where the hub diameter is the thin hub diameter.
In other words, the value range of the rotational period ratio of a video tape having the thick hub diameter overlaps with that of the rotational period ratio of a video tape having the thin hub diameter. Generally, as the amount of tape having the thick hub diameter is larger than that of a tape having the thin hub diameter, if the video tape having the thick hub diameter is subjected to the same control as the control for the video tape having the thin hub diameter, then even when a forward/rewind position approaches the tape end position, deceleration is not performed and stoppage in an appropriate position is not made. Accordingly, in order to avoid any inconvenience by performing the thin hub video tape control on the video tape having the thick hub diameter, the control for the video tape having the thin hub diameter is performed only if it is determined by the detected rotational period ratio that the video tape cannot be a tape having the thick hub diameter, and thereafter, the control for the tape having the thin hub diameter is performed until the video tape is ejected.
As described above, in the present invention, as the high-speed tape forward control is performed in accordance with the rotational period ratio between the supply reel and the take-up reel, even though hub diameter discrimination is not necessary, the same advantage as that obtained by hub diameter discrimination can be obtained as the FF/REW progresses. Accordingly, a FF/REW control apparatus capable of performing high-speed tape forward in a simple manner can be provided.
In this manner, in the present invention, as the hub diameter is not directly discriminated (but rather the ratio between the rotational periods of the supply reel and the take-up reel is discriminated), a high-speed tape forward mode is executed immediately after the request for high-speed tape forward. Further, even though the hub diameter is not known immediately after starting high-speed tape forward, the hub diameter of the loaded video tape is discriminated as the FF/REW progresses, hence appropriate control can be performed on video tapes having respective hub diameters.
As described above, the VHS-format video tapes include tapes having a hub diameter of 62 mm and tapes having a hub diameter of 26 mm. The former corresponds to a thick hub and the latter, a thin hub. Further, in FF and REW, the only difference is that the tape forward directions are opposite to each other. Accordingly, for the case where the above rotational period ratio is Tt/Ts (Tt being the rotational period of the take-up reel, and Ts being the rotational period of the supply reel) in FF, and the rotational period ratio is Ts/Tt in REW, since it is preferable that the value increases as time elapses in both FF and REW, the threshold values used to control the acceleration and deceleration can be the same.
The VHS-format video tapes include thick-hub tapes and thin-hub tapes, and further, video tapes having hub diameters out of the above specification. Accordingly, it is preferable to avoid any inconvenience even if such out-of-spec hub diameter video tapes are used. As an example of such a construction, according to another aspect of the present invention, in the FF/REW control apparatus, the tape-forward control unit performs thick hub diameter high-speed tape forward control when the rotational period ratio has a value other than the values for a video tape having an out-of-spec hub diameter.
In the present invention as constructed above, if the rotational period ratio has a value other than values of the video tape having the out-of-spec hub diameter, the high-speed tape forward control for a thick hub is performed. That is, the value ranges of the rotational period ratio of video tapes having thick and thin hub diameters overlap with that of the rotational period ratio of video tapes having out-of-spec hub diameter, and generally, the value rage of video tape having the out-of-spec hub diameter is within the value range of the video tape having the thick and thin hub diameters. Accordingly, to avoid inconvenience caused by performing control for video tapes having the thick and thin hub diameters on a video tape having the out-of-spec hub diameter, the control for a thick hub is performed only if it is determined by the detected rotation ratio that the video tape is not out of specification. If it is further determined that the hub is not a thick hub, then control for a thin hub is performed.
Accordingly, the present invention can be applied to a case where a video tape having an out-of-spec hub diameter is loaded.
Note that as described above, generally, the rotational period ratios of the video tape having the out-of-spec hub diameter, the video tape having the thick hub diameter, and the video tape having the thin hub diameter overlap with each other. According to another aspect of the present invention, as a particular example of these rotational period ratio value ranges, in the FF/REW control apparatus, the tape-forward control unit determines that the rotational period ratio has a value other than the values of the video tape having the out-of-spec hub diameter if the rotational period ratio is out of a range of 0.8 to 1.2, and determines that the rotational period ratio has a value other than the values of the video tape having the thick hub diameter if the rotational period ratio is out of a range of 0.6 to 1.7.
In the present invention constructed as above, the possible value range of the rotational period ratio of a video tape having the out-of-spec hub diameter is 0.8 to 1.2, that of a video tape having the thick hub diameter is 0.6 to 1.7, and a range beyond these ranges is a value range of a video tape having the thin hub diameter, that is, generally the value of the rotational period ratio is within a range of about 0.3 to 3.3. In the case of a thin hub, the rotational period ratio has any value within the entire range; in the case of a thick hub, the rotational period ratio is from 0.6 to 1.7; and in the case of an out-of-spec hub, a value ranges from 0.8 to 1.2. The above-described control is performed with these ranges as respective value ranges.
Accordingly, control can be performed in accordance with the respective hub diameters by discrimination of the rotational period ratio.
Note that upon high-speed tape forward, various constructions may be made as long as it can forward the tape at a speed higher than a normal speed. Accordingly, as one example of such a construction, according to another aspect of the present invention, in the FF/REW control apparatus the tape-forward control unit controls the high-speed forward so as to accelerate a tape running speed to a higher speed as an initial value of the rotational period ratio becomes smaller in the case where the hub diameter is the thick hub and in the case where the hub diameter is the thin hub. When the rotational period ratio is greater than a predetermined value, the tape-forward control unit decelerates the tape running speed.
In the present invention constructed as above, in high-speed tape forward in case of thick hub and in high-speed tape forward in case of thin hub, the tape-forward control unit controls the tape forward such that as the initial value of the rotational period ratio gets smaller, the tape forward is accelerated to a higher speed, and when the rotational period ratio is equal to or greater than the predetermined value, the tape forward is decelerated. That is, in a video tape, the smaller the rotational period ratio, the smaller the amount of tape wound on a reel on the tape-forwarded side. Conversely, the larger the rotational period ratio, the greater the amount of tape wound on a reel on the tape-forwarded side. Accordingly, as the initial value of the rotational period ratio becomes smaller, the FF/REW is accelerated to a higher speed. Further, to prevent the FF/REW from passing a tape end position while performing high-speed FF/REW, the high-speed FF/REW is decelerated when the rotational period ratio becomes greater than the predetermined value.
Accordingly, high-speed tape forward control can be performed with simple discrimination in accordance with the amount of remaining tape.
More specifically, when controlling for a thick hub, the rotational period ratio is divided into 5 ranges, i.e., less than 0.7, as an initial value, then 0.7 to 0.8, then 0.8 to 0.9, then 0.9 to 1.0, and then greater than 1.0. When the rotational period ratio is less than 0.7, the high-speed tape forward is accelerated 18 times its higher speed; when the ratio is 0.7 to 0.8, the high-speed tape forward is accelerated 15 times its higher speed; when the ratio is 0.8 to 0.9, the high-speed tape forward is accelerated 12 times its higher speed; when the ratio is 0.9 to 1.0, the high-speed tape forward is accelerated to 9 times its speed; and when the ratio is greater than 1.0, the high-speed tape forward is accelerated to a sextuple speed. In a case where the initial value of the rotational period ratio is less than 0.8, the high-speed tape forward is decelerated to the sextuple speed when the rotational period ratio becomes greater than 0.9; in a case where the initial value of the rotational period ratio becomes greater than 0.8, the high-speed tape forward is decelerated to the sextuple speed when the rotational period ratio is greater than 1.0.
Further, in the above-described control for a thin hub tape, the possible value range for the thin hub is divided into 5 ranges, and a target accelerated speed is determined based on the range to which the initial value of the rotational period ratio belongs. Then, deceleration is started when the rotational period ratio goes over a predetermined value. As a result, the smaller the initial value of the rotational period ratio, i.e., the larger the forwardable amount of remaining tape, the tape forward is accelerated to a higher speed, then the tape forward is decelerated when the forwardable amount of tape becomes less than a predetermined amount. Thus, high-speed tape forward is performed in accordance with the forwardable amount of tape.
In this manner, in the above-described present invention, since high-speed tape forward can be performed without directly discriminating the hub diameter, the operating mode can be moved to a high-speed tape forward mode immediately after starting FF/REW. As a more particular example of such construction, according to another aspect of the present invention, in the FF/REW control apparatus, the tape-forward control unit quickly performs high-speed tape forward control in accordance with the rotational period ratio calculated by the rotational-period-ratio calculation unit immediately after starting FF/REW.
In the present invention constructed as above, the tape-forward control unit immediately performs the high-speed tape forward control for the above-described thick hub and thin hub (or control for out-of-spec hub), in accordance with the ratio between the rotational periods of the supply reel and the take-up reel detected immediately after the start of FF/REW. Accordingly, the operating mode can be moved to the high-speed tape forward mode immediately after the start of FF/REW.
Accordingly, the high-speed tape forward can be performed immediately after the start of FF/REW.
According to another aspect of the present invention, a FF/REW control apparatus is provided comprising: a supply reel and a take-up reel, provided in a position where a video tape is loaded and being rotatable while engaging with hubs of the video tape; a reel motor, connectable via an idler to one of the supply reel and the take-up reel and being capable of speed-variably driving any one of the reels in a predetermined direction; rotational period sensors that respectively detect rotational speeds of the supply reel and the take-up reel; end sensors that respectively detect a start end and a terminal end in the video tape; and a system controller, connected to the rotational period sensors, the end sensors and the reel motor, that calculates a rotational period ratio between the rotational speeds of the supply reel and the take-up reel based on the result of outputs from the rotational period sensors when high-speed tape forward is performed on the video tape until the start end or the terminal end is detected by the end sensors, and performs high-speed tape forward control for a thick hub if the rotational period ratio has a value within a value range of a video tape having a thick hub diameter, while performing high-speed tape forward control for a thin hub if the rotational period ratio has a value outside of the value range of the video tape having the thick hub diameter.
In the present invention constructed as above, when a video tape is loaded, the supply reel and the take-up reel engage with hubs of the video tape and become rotatable. The reel motor is connected via the idler to one of the supply reel and the take-up reel and enters a status possible to drive with a variable speed the tape in the predetermined direction. on the other hand, the end sensors are provided to detect the start end and the terminal end of the video tape. The system controller performs the high-speed tape forward on the video tape until the start end or terminal end is detected by the end sensors. At this time, the system controller calculates the rotational period ratio between the rotational periods of the supply reel and the take-up reel based on the result of outputs from the rotational period sensors. If the rotational period ratio has a value within the range of a video tape having the thick hub diameter, the system controller performs the high-speed tape forward control for a thick hub, and when the rotational period ratio has a value outside of the range of the video tape having the thick hub diameter, it performs the high-speed tape forward control for a thin hub.
In this manner, it can be understood that the high-speed tape forward control in accordance with the rotational period ratio between the supply reel and take-up reel is not limited to a device having a material substance, but realized as a method. According to another aspect of the present invention, a FF/REW control method is provided for performing, upon execution of FF or REW while varying a tape running speed of a loaded video tape, high-speed tape forward in a case where a hub diameter of the video tape is a thick hub diameter and high-speed tape forward in a case where the hub diameter is a thin hub diameter, comprising the steps of: detecting rotational periods of a supply reel and a take-up reel of the video tape; calculating a rotational period ratio between the detected rotational periods of the supply reel and the take-up reel; and performing high-speed tape forward control in the case where the hub diameter is the thick hub diameter if the calculated rotational period ratio has a value within a value range of a video tape having the thick hub diameter, while performing high-speed tape forward control for a thin hub diameter if the rotational period ratio has a value outside of the value range of the video tape having the thick diameter.
That is, the present invention is applicable to not only a medium having a material substance but also a method.
The FF/REW control apparatus may be implemented as a single apparatus, or may be utilized in a status where it is incorporated into another apparatus. Thus, the idea of the invention is not limited to the apparatus having the above construction, but includes various aspects such as hardware and software and may be arbitrarily changed.
Further, in a case where the present invention is implemented by software for the FF/REW control apparatus as a particularly implemented example of the idea of the invention, the invention exists and can be utilized on a medium containing such software.
As an example, according to another aspect of the present invention, a medium is provided in which a FF/REW control program to be performed by a computer is stored. Upon requesting FF or REW while varying a tape running speed of a loaded video tape, high-speed tape forward is performed in a case where a hub diameter of the video tape is a thick hub diameter and in a case where the hub diameter is a thin hub diameter. The program comprises: detection process procedure code for detecting rotational periods of a supply reel and a take-up reel of the video tape; calculation process procedure code for calculating a rotational period ratio between the detected rotational periods of the supply reel and the take-up reel; and control process procedure code for performing high-speed tape forward control in the case where the hub diameter is the thick hub diameter if the calculated rotational period ratio has a value within a value range of a video tape having the thick hub diameter, while performing high-speed tape forward control in the case where the hub diameter is the thin hub diameter if the rotational period ratio has a value outside of the value range of the video tape having the thick diameter.
The medium may be a magnetic recording medium or an opto-magnetic recording medium, or further, may be any recording medium to be developed in the future. Further, duplicates including primary and secondary duplicates can be considered to be equivalent to the above recording medium. Further, the present invention can be applied to a case where the invention is supplied via a communication line.
Further, the idea of the invention does not change at all when the invention is realized in part by software and in part by hardware. Further, the present invention is applicable to a case where a part of the invention is stored in a recording medium and it is arbitrarily read as necessary.
In this manner, to realize the present invention by software, hardware and an operating system may be utilized, or the present invention may be realized separately from the hardware and operating system. For example, the processing may be performed by reading a predetermined function in the operating system, or may be performed by inputting such function from the hardware. Even in a case where the invention may be actually realized via the operating system, it can be understood that in the progress of recording the program into the medium to be delivered to users, the present invention can be implemented only by the program.
Further, in a case where the present invention is implemented by software, the invention is realized as a medium containing a program. Further, the present invention is realized as the program itself. The program itself is included in the present invention.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same name or similar parts throughout the figures thereof.